Denitrifier-tungsten disulfide biohybrid system-based pyroelectric bio-denitrification driven by temperature fluctuations

Bio-denitrification is a crucial process in wastewater treatment plants (WWTPs). While abundant thermal energy has been shown to induce temperature fluctuations for pyro-catalysis, its potential synergy with bio-denitrification has not been explored. We introduce a pyroelectric bio-denitrification process, where renewable thermoelectric energy from temperature fluctuations is harnessed using pyroelectric materials to drive the metabolism of autotrophic denitrifiers. We develop a biohybrid system composed of Thiobacillus denitrificans (T. d) and tungsten disulfide (WS2), enabling complete pyroelectric bio-denitrification over three successive 5-day cycles with room temperature fluctuations as small as 5 , significantly reducing energy consumption for temperature control. Mechanical analysis reveals that WS2 can either precipitate on the cellular surface or be internalized by T. d, with the generated pyroelectric charges serving as efficient reducing equivalents to facilitate the denitrification process. Implementing in actual wastewater treatment, the denitrifier-WS2 biohybrid system achieves a maximum 8.09-fold increase of nitrate removal under natural temperature fluctuations, comparing to conditions without temperature variation. Life-cycle assessment and cost analysis demonstrate that pyroelectric bio-denitrification offers significant environmental and economic benefits over traditional processes. Our findings highlight the considerable potential of the pyroelectric effect in enhancing bio-denitrification, offering valuable insights for a paradigm shift in WWTPs